- #1
salman213
- 302
- 1
1. A toy gun fires a 9.41-g projectile disc by using a compressed sprint (k=1.72 x 10^3 N/m) and a 13.1 cm long barrel. As the disc travvels through the barrel it experiences a constant frictional force of 0.13 N. If the spring is compressed 14 mm what is the speed of the disc as it leaves the gun?
2. Ek = 1/2mv^2
Ee = 1/2kx^2
W = F*d
3. DeltaEe - W = DeltaEk ?
1/2kx^2 - F*d = 1/2mv^2
1/2(1.72 x 10^3)(0.014)^2 - (0.13*0.131) = 1/2(0.00941)(v)^2
v = 5.67 m/s BUT THATS WRONG, I have a physics exam some day this week and i was just reviewin gmy notes and trying old review problems he gave us..and on the review it says the answer to this question is 1.8 m/s...i don't get what I am doing wrong :(
2. Ek = 1/2mv^2
Ee = 1/2kx^2
W = F*d
3. DeltaEe - W = DeltaEk ?
1/2kx^2 - F*d = 1/2mv^2
1/2(1.72 x 10^3)(0.014)^2 - (0.13*0.131) = 1/2(0.00941)(v)^2
v = 5.67 m/s BUT THATS WRONG, I have a physics exam some day this week and i was just reviewin gmy notes and trying old review problems he gave us..and on the review it says the answer to this question is 1.8 m/s...i don't get what I am doing wrong :(